Tube of flexible composite sheet material and the manufacture thereof



APril 27, 1948. l w. LANIGER 2,440,339

TUBEOF FLEXIBLE COIPOSITE SHEET MATERIAL AND IHEW MANUFATURE THEREOF Filed Nov. 24, 1942 2 Sheets-Sheet 1 22 25 f 2 da l: v.1 4. 7 lNvENfQR ATTORNEYS w. LANGE 42,440,339

ERIAL AND THE MANUFACTURE THEREOF April 27, 194s.

Y TUBE OF FLEXIBLE COMPOSITE SHEET HAT Filed NIOV. 24, 1942 2 Sheets-Sheet 2 Patented Apr. `27, 1948 UNITED s'rA'rEs PATENT ,OFFICE TUBE F FLEXIBLE COMPSITE SHEET MATERIAL AND THE MANUFACTURE THEREOF Walter Langer, New York, N. Y. 4implication November 24, 1942, Serial No. 466,724

ample, toothpaste, cold cream, oil colors andthe like. i

Heretofore collapsible tubes of the character aforesaid for packaging materials of a plastic ,or pastelike consistency have been made with a relatively rigid head portion and a tube portion of flexible sheet material that is secured to the head portion, the tube portion being made of tin or of a tin alloy. Usually both the head and tube portions are composed of tin or tin alloy. However, it has also been proposed to substitute other materials for tin or tin alloys in both the head portion and the tube portion of tubes of the type in question. Thus it has been proposed to use paper, cellulose films, etc., as the flexible sheet material of the tube portion of collapsible tubes. It has also been proposed to use various molded plastic materials, wood, metal,etc., -as the head portion of such tubes. However, collapsible tubes which utilize as a substitute some material other than tin or tin alloys have not been successful commercially due to a number of factors. Thus, when paper, sheet cellulose or the like is used as the flexible sheet material oi' the tube portion, the sheet material is not sufllciently impermeable either to water or to'oils, regardless of the type of irnpregnating or coating materials heretofore suggested for rendering such sheet material impermeable. Moreover, regardless of the original impermeability of the sheet material, it' tends to develop cracks and flaws during manufacture and assembly of the tube and as a result of ilexure during usage. Moreover, many materials react disadvantageously with the contents of the tube and this greatly limits the type of substance that can be used in direct contact with the'contents of the tube. -V

s claims. (C1. 13e-53) tube, said application having Ibeen abandoned, I have disclosed the employment of wcrepe metal foil integrally bonded with-a base sheet of paper, fabric, sheet cellulose, or the like as the tube portion of collapsible tubes.

In the manufacture of tubes consisting entirely of metal such as tin or tin alloy, the tube can be made of seamless construction. Elaborate mechanisms for producing thin tubular metal bodies which are seamless are resorted `to in order to eliminate the dilculties lthat are incident to the occurrence in the tube body of a collapsible tube of a longitudinally-extending seam. While, as a manufacturing operation, -it is less expensive to wrap thin sheet metal about a mandrel and cause the metal to adhere at a longitudinal seam, no satisfactory method has been proposed, so far as I am aware, for producing a `permanent and liquid-tight seam. When a metal foil is used as a surfacing for a sheet of paper or the like, production of seamless tubing is not possible and it becomes necessary to provide a longitudinal seam. Attempts have heretofore been made to seal overlapping ends of composite sheet material carrying metal foil on one side thereof by means of an adhesive. However, in attempting to bond the inner or non-metallic surface of the sheet As aforesaid, one of the problems incident to providing a flexible sheet material other than an all-metal sheet such as a sheet composed of tin -or tin alloy is that of providing impermeability to water and to oil. When the flexible sheet material contains as a base some substance other than metal, e. g., paper, fabric, sheet cellulose, or the like, impermeability can be afforded by providing adherent to a surface thereof and integral therewith a'metal foil. Metal foil can be made extremely thin while preserving its impermeability to Water and to oil. .In my application Serial No. 464,034, filed Octoberl, 1942, for Collapsible material with the outer metal foil surface, the adhesion is defective. The seam tendsto pull apart and points of leakage are likely to develop. This is very undesirable, not only due to possible loss of contents of the tube, but also from the point of view of gradual drying out and hardening of the contents of the tube, so that the contents become unusable. Moreover, any,r oily material which exudes gradually from a tube is highly objectionable due to its soiling tendency.

It is a purpose of this invention to provide a tube construction and a method of making tubes whereby a permanent liquid-tight seam is provided utilizing'flexiblecomposite sheet material containing metal foil.V It is a further purpose of this invention to provide a liquid-tight seal at -one end of a tube `of flexible sheet material.

According to one feature ofthe present invention, a sheet of flexible composite sheet materialcomprising a strain-resisting sheet of non-metallic sheet material, one surface of which carries v integrally therewith a layer of metal foil, the opposite surface being non-metallicP-is` formed into la tube which is characterized by a longitudinally-extending seam and which is further characterized by the fact that, inthe region of the seam, longitudinally-extending portions of the non-metallic surface of the ilexible composite sheet material are brought into juxtaposition and are bonded together face-to-falce with adhesive material that is between the juxtaposed portions of the non-metallic surface of the sheet. In preferred construction, the flexible composite sheet material extends beyond the primary seal in the zone of initial juncture of the flexible composite sheet material so as to provide an extensionfwhich is wrapped about the tube for a substantial distance, the end of the extension being bonded to the surface of the tube. Preferably, the extension is wrapped in such direction that the non-metallic surface of the strain-resisting sheet is outermost and is carried about the tube beyond the region of the primary seal, fthe end of the extension being turned under to provide a non-metallic surface which is made adherentto the exposed non-metallic 'surface of the extension. Alternatively, the extension may be wrapped about the tube in the opposite direction, namely, so that the metallic surface is outermost, and the non- -metallic surface thereof made adherent to exposed metal surface of the tube.

In the manufacture of tubes having the structure aforesaid, it is preferable to employ, at least in the region where the sealing .is to take place, an adhesive of the heat-sealing type. Such adhesive may be thermoplasticresin such as a vinyl resin or a thermo-setting resin such as a phenolaldehyde type resin. According to this invention, the flexible composite sheet material is made into a tube and in the zone of initial juncture of the flexible sheet material the juxtaposed non-metaland which are bonded together with insoluble bonding materials, the contents of the tube can be effectively prevented from contacting with the metal foil layer ofthe flexible composite sheet material in such way as to contaminate the contents of the tube. For example, on the inner side of the primary strain-resisting sheet, a sheet of waterproof sheet cellulose may be made adherent by an insoluble adhesive. The primary strain-resisting sheet is made adherent to the metal foil by another layer of insoluble adhesive material. Moreover, the outermost surface of the waterproof sheet cellulose layer can be given a coating of insoluble material. Preferably, this exposed coating on the non-metallic side of the I flexible composite sheet material is composed of lic surfaces thereof are subjected to heat with the heat-sealing adhesive therebetween, thus producing an impervious and permanent seal in this zone. Thereafter, when an extension of the ilexible composite sheet material is wrapped about the tube, the end thereof can likewise be made adherent by employment of heat using a heatsealing type of adhesive between the surfaces to be bonded together.

It is a further feature of this invention that the end of the tube may be conveniently sealed so as to provide -a liquid-tight sea1 at the end of the tube by pressing together opposite sides of the tube with a heat-sealing type of adhesive between the surfaces to be bonded together. When the interior of the tube is lined with a material such as paper, fabric, sheet cellulose or the like, a very permanent and highly impervious sea1 'can be provided at the end of the tube utilizing a heat-sealing type of adhesive.

Itis an advantage of the present invention that metals more generally available than tin may be used. For example, lead or aluminum foil may be used. Lead is objectionable when used in direct contact with the contents of tubes when the tubes contain materials such las toothpaste, cold cream or the like which are to be introduced into the mouth or applied to the skin due to tendency of material in the tube to absorb leadv with the resulting Possibility of lead-poisoning. Alumia thermoplastic material which can be used to eect a seal merely'by application of heat in the manner hereinabove mentioned.

In connection with the foregoing, it is to be noted that, not only throughout the body portion of the tube, but also in the region of the sea1, the contents of the tube are at all times out .of contact with the metal foil. With the ordinary type of overlapping seam, the edge of the metal foil'comes in contact with the contents of the tube even though the metal foil is uned.-`

Further purposes, features and advantages of this invention will be apparent in connection with the following description of certain embodiments of this invention which are shown for illustrative vpurposes only in the accompanying drawings,

wherein y Figure 1 is a transverse section of a tube of flexible composite sheet material according to this invention; Y 4 f Fig. 2 is a fragmentary section on a greatly enlarged scale of the v'seam portion of the tube shown in Fig. l;

Fig. 3 is a transverse section of an alternative' embodiment of the present invention;

Fig. 4 is a transverse section on a greatly enlarged scale of the seam portion of the tube shown in Fig. 3;

Fig. 5 is a longitudinal sectional elevation of a collapsible tube showing a tube portion of flexible composite sheet material according to the present num foil is attacked by alkaline materials and cannot be used except in connection Kwith the packaging of non-alkaline material. In using the construction of the present invention, the lining of the tube is composed of the strain-resisting sheet material together with suitable impregnating and bonding materials which prevent the contents of the tube from coming in contact with the metal foil.

Especially when a plurality of layers of nonl metallic sheet material are used which are impregnated with insoluble impregnating materials invention attached at one end to a head portion and sealed at the other end;

Fig. 6 is a fragmentary sectional view on a greatly enlarged scale taken on the line S--G ofl Fig. 5;

Fig. 7 is a fragmentary sectional view on a greatly enlarged scale of a preferred type of flexible composite sheet material for use according to the present invention;

Fig. 8 is a` transverse section of tubing that illustrates a preliminary step in the manufacture of a tube of the type shown in Figs. 1 and 2;

Fig. 9 is a transverse section of tubing that :illustrates a step that follows the step illustrated in Fig. 8;

Fig. l0 is a transverse section of tubing that illustrates an initial step in the manufacture of the embodiment of the present invention shown sheet material which comprises a ammesseing foundation sheet 2l which, forexample, may

l On the opposite side of the Aflexible composite sheet material is a coating which is normally nonsticky but which, when subjected to heat, becomes sticky and adhesive and is adapted to act a's a bonding material. This coating 23, for brevity. will be referred to as an adhesive coating. The

' coating 23 presents the interior surface of the tube and is therefore referred to as being on the inner side of the flexible composite sheet material. 'I'he metal foil 22 is referred to as being on the outer side of the flexible composite sheet material.

Referring to the composite sheet material as a whole. the surface of the composite sheet material opposite to the metal foil 22 is referred to for the sake of brevity as the non-metallic surface of the flexible composite sheet material. The nonmetallic" surface of the flexible composite sheet material does not present a metal surface or a metal surface carrying adhesive directly on metal. The non-metallic" surface of the flexible composite sheet material is the surface presented by a non-metallic sheet of paper. fabric, sheet cellulose or the like, either coated or non-coated with adhesive or other coating.

, Referring to Fig. 1, no attempt is made to show the different layers 2l, 22 and 23 of the composite sheet material, although it is to be understood that the sheet material of the tube shown in Fig. 1 is of the character shown on a greatly enlarged scale in Fig. 2 and describedhereinabove. In Fis. 1, the inner or primary tube-forming layer of the flexible'composite sheet material is indicated by the reference character a and the outer layer which is an extension of the layer 20a is indicated by the reference character 20h.

The inner layer 20a of the flexible composite sheet material is formed as a tube and, in the zone of initial juncture of tlfe exible composite sheet the primary layer 20a of the tubing about a mandrei 24. In the zone of initial juncture of the flexible composite sheet material, the flexible composite sheet material is bent outwardly with longitudinally-extending portions of the inner non-metallic surface thereof in juxtaposition.

c pressure.

material. it is to be noted that longitudinally extending portions of the non-metallic surface of the flexible composite sheet material are brought into juxtaposition and are sealed face-to-face by the adhesive material 23. Thissealed seam in the zone of initial juncture of the flexible composite sheet material is referred to as the primary seal and is indicated in Figs. 1 and 2 by the reference character 24.

The flexible composite sheet material. whichis folded back on itself at the primary seal to provide the juxtaposed portions of non-metallic surface that are sealed face-to-face, is carried back from the region of the primary seal 24 and is wrapped about the primary tube (consisting of the layer 20a) to provide the extension 2Gb, and it is to be noted that in this extension the adhesive layer 23 is outermost. The extension 20h is carried about the outside of the tube beyond the region of the primary seal 24 until the end thereof overlies non-metallic surface of the extension of the flexible composite sheet material. The end of the extension has an inwardly turned portion 25 which presents a non-metallic surface portion that is in juxtaposition with a portion of the non-metallic surface of the extension 20h, these portions of the non-metallic surface being bonded face-to-face by the adhesive coating 23.

Referring to Figs. 8 and 9, the steps in the manufacture of a tube of the structure shown in Figs. 1 and 2 may be conveniently carried out by wrapping the composite flexible sheet material to form The inner non-metallic surface of the fiexible composite sheet material is, as aforesaid, provided with a coating which is of the heat-sealing type. Therefore, by use of suitable heated members- 21, the primary seal 24 can be made by pressing the juxtaposed portions of the non-metallic surface of theflexible composite sheet material together, utilizing the members 21 which, being heated, cause the adhesive of the coating 23 to become activated so as to bond the juxtaposed portions face-to-face. Since each of the opposed non-metallic surfaces of the exible composite sheet material carries the coating 23, the heatsealing step can be carried out effectively with only an extremely brief application of heat and After the primary seal 24 has been formed in the manner illustrated in Fig, 8, the extension 20h is wrapped about the mandrel 26 as shown in Fig. 9, and the turned-over end portion 25 of the extension 20h can be bonded in place by `use of the heated pressing member 28 which presses the turned-under non-metallic surface of the flexible composite sheet material against the underlying non-metallic surface of the extension 20h, and, since both of these surfaces oarries the adhesive coating 23, the end of the extension 20h is effectively and rapidly bonded in place.

The advantages of the construction and method shown in Figs. 1, 2, 8 and 9 are several. In the first place. the seal which is produced and which i-s relied upon both for maintaining the integrity of the tube and for preventing seepage of the contents therefromis effected by an adhesive bond that is between non-metallic surface portions of the flexible composite sheet material. In this manner, an effective seal which is permanent and which is impervious to water and oils can be provided notwithstanding the employment of a composite flexible sheet material which carries va metal foil that inherently does not lend itself l to permanent and impervious bonding by means of adhesive materials. Furthermore, the primary seal .which is effected at the initial juncture of the flexible composite sheet vmaterial is such that the contents of the tube are sealed without coming in contact with the metal of the metal foil. It is to be noted that none of the edge portion of the metal foil comes in contact with the contents of the tube.

It is a further advantage of the preferred emy .bodiment of this invention shown in Figs. l and `2 that the flexible compositesheet material is provided with an extension which is wrapped about the tube so that the end thereof may be bonded in place by a seal effected by juxtaposed non-metallic surfaces of the flexible composite sheet material. Furthermore, the employment .of the Wrapped-aroundv extension of the flexible composite sheet material gives bulk to the wall of the tube so that it will have mechanical properties closely resembling the mechanical properties of tubing made entirely of tin or of lead-tin alloy of the type heretofore used in the packaging of plastic and 'semi-fluid materials. Moreover, a double thickness of the metal foil is provided so that, notwithstanding possible occurrence of a flaw in the metal foil, the secondary layer of metal foil will provide good` insurance against the chiasso occurrence of points of permeability due to the possible occurrence of flaws in the metal foil.

The exterior of the tube shown in Figs. 1 and 2 may be provided with any suitable ornamentation. In this connection, the external coating of heat-sealing adhesive 23 provides an excellent base for the application of an ornamental paint, lacquer or the like such as are customarily used ior ornamenting, and for providing suitable lettering, designs, etc., on collapsible tubes. No attempt in Figs. 1 and 2 has been made to show any suchexternal ornamental layer.

Referring to Figs. 3 and 4, an alternative embodiment of this invention is shown. In this embodiment, the iiexible composite sheet material may, for purposes of illustration, be similar to that shown in Figs. 1 and 2 and may comprise the strain-resisting sheet 2|, the outer layer 22 of metal foil integral with the sheet 2l and an inner layer 23 of 'normally non-sticky adhesive 23. The inner or primary layer 30a of flexible composite sheet material is formed as a tube with the non-metallic surface of the flexible composite sheet material on the inside. At the zone of initial juncture of the flexible composite sheet material, there is a turnedback end 3i which presents a longitudinally-extending portion of non-metallic surface that underlies another longitudinally-extending portion of the non-metallic surface of the iiexible composite'sheet material, these non-metallic portions being integrally bonded together by the adhesive of the layer 23 to form the primary seal 32. The flexible composite sheet material is carried beyond the primary seai 32 with the layer 22 of metal foil outermost to provide the extension 30h which is wrapped around the tube and which terminates as shown in the region of the primary seal 32.-

In making a tube such as that shown in Figs. 3 and 4, and referring to Figs. l0 and 11, the exible composite sheet material may advantageously be Wrapped about the mandrel 26 and the primary seal 32 effected by pressing together outwardly-extending portions of the exible composite sheet material having non-metallic surfaces in juxtaposition. By pressing these juxtaposed portions together, using the heated pressing members 2l, the adhesive in the coating 23 of the juxtaposed surfaces is activated and the primary seal is effected. The extension 30h is then wrapped about the primary layer 30a of the flexible composite sheet material and the end thereof is pressed in place by the heated pressing member 2S to bond the end thereof to the.underlying flexible composite sheet material. If desired, in making this modification, the entire extension 30h may be hot-pressed against the layer 30a so as to cause the adhesive 23 to adhere to the underlying layer 33a throughout the full extent of the extension 30h, thereby providing greater stifliness to the wall of the tube. Also, if desired, additional adhesive material of the heat-sealing type may be employed adjacent the end of the extension 3b by application of the adhesive to the surface to which the end of the extension 30h is to become bonded. If desired, the outer surface of the tube may have an ornamental coating of paint. lacquer or the like applied thereto.

In Fig. 5, a tube of .flexible composite sheet material is shown as constituting the tube portion of acollapsible tube, the tube portion being united to a suitable head portion. The head portion is preferably of the structure shown in my application Serial No. 464,034 hereinabove referred to. In Fig. 5, the head portion is shown for purposes of illustration as including a head body 35 having a removable cap 33 which acts as a closure for the passage 31 through the head body. The tube of flexible composite sheet material is attached to the head body by the clamping ring 38, the flexible composite sheet material being brought up over the outside of the clamping ring 38 and folded inwardly as shown so as to securely hold the tube portion in place with the composite sheet material between the peripheral face of the head portion and the inside of the upstanding wall portion of the clamping ring. The -tube portion is shown in Fig. 5 i'or illustrative purposes as being composed of two layers 49a and 49h of ilexible composite sheet material and these layers may be disposed in the manner shown in Figs. 1 and 2 or in Figs. 3 and 4, or otherwise in accordance with the present invention. The tube portion is shown as including the longitudinally-extending seam 39 which may be of the type shown in Figs. 1 and 2 or the type shown in Figs. 3 and 4, or otherwise in accordance with the present invention.

In Fig. 6, closure means for the lower end of the tube is shown, the layers of flexible composite sheet material being disposed for purposes of illustration as shown in Figs. 3 and 4. The end of the tube is brought together to provide the fold 40, the fold 40 being held in place by the staples 4l. Alternatively, a metal clip of usual construction may be used to hold the fold in place. It is of l members 42. thereby bonding together these portions of non-metallic surface of the flexible composite sheet material. Thereafter the sealed end portion of the tube may be folded over and secured bystaples as shown in Fig. 6. It is apparent that when the flexible composite sheet material' in the wall of the tube is disposed as shown in Figs. 1 and 2 the end of the tube may be heat-sealed in a similar manner.

It is, of course, not essential that the head portion of a collapsible tube be of the structure shown in Fig. 5, although it is preferable to employ as the head portion to which the tube portion is secured a structure of any of the types described and covered in my said application Ser. No. 464,034. However, other types of head portion may be availed of. The head portion may be made of any suitable material such as formed plastic, Wood, glass, metal, etc., as may be desired.

While the tube portion of flexible composite sheet material may be secured to the yhead portion merely by mechanical clamping, it is preferable in the practice of this invention to apply to the surfaces of the head portion that are to contact theiiexible composite sheet material an insoluble cementatory material. A thermoplastic cementatory material such as avinyl resin, or a sulfamide-formaldehyde resin is well suited for this purpose, although a cementatory material of the heat-setting type may be employed, such as a phenol-aldehyde resin. Preferably, the insoluble cementatory material is similar to that employed for the coating 23. Thus the clamping ring 38 and/or the peripheral face 50 of the a layer of heat-sealing adh'esive.

head body may be coated as by spraying. brush zone of the juncture between the tube body and the head portion of the collapsible tube may be heated to effect a heat-sealing of the cementatory material, thus pviding an impervious and permanent union between the head and tube portions of the collpasible tube. Especially when the assembled tube body presents a coating of the heat-sealing type both on the inside and on the outside, e. g.. as in Figs. l and 2, the cementatory adhesion of the surfaces of the flexible composite sheet material to the contacting portions of the head body is very eiectively and quickly attained.

. In the embodiment shown in Fig. 5, this cementmerely illustrative and that embodiments of this invention may take a variety of forms. In the embodiments of this invention above described, the extension ofthe flexible composite sheet material that is carried beyond the region of th'e primary seal is wrapped around the tube so that the end of 'the extension occurs in the region of the primary seal. This is regarded as preferred construction, but is not essential, Thus the extension may be wrapped only partof the distance around the tube or may be wrapped throughout a plurality of turns about the tube. Likewise, th'e tube may be made without including the extension of the ilexible composite sheet material that is wrapped about the tube. While the non-metallic surface of the exible composite sheet material is shown disposed so as to provide the inner surface of the tube, it is possible to practice this invention utilizing the metal foil on the inside of the tube. However, it is regarded as preferable, especially when some material, such as lead, is employed as the metal foil, to use the non-metallic surface of the exible composite sheet material as the interior of the tube and. at the initi-al juncture of the flexible composite sheet material, to seal together face-to-face portions of the non-metallic surface o1' the flexible composite sheet material without exposing any portion of th'e metal foil of the flexible composite sheet material to the contents of the tube.

The flexible composite sheet material may t-ake several different forms. In Figs. 2, 4 and 6, the flexible composite sheet material has been shown as comprising a strain-resisting sheet, an adherent layer of metal foil, and on the side of the strain-resisting sheet opposite from the metal foil, Preferably, however, the flexible composite sheet material is made as illustrated in Fig. 7. In this figure, the strain-resisting sheet is likewise composite in character and includes a sheet 45 which may be fibrous in character such as paper, fabric or the like. The sheet 45 has adherent thereto an essentially impervious sheet 46 such as sheet cellulose. Preferably, the sheet cellulose is of the waterproofed type so that it will be as nearly as possible impervious to liquids. For example, sheet cellulose which h-as had deposited thereon a film 'of insoluble soap or the like may be used. The

sheet lcellulose 46 is bonded to the sheet 45 by a suitable adhesive 41 which is insoluble and which may be, for example, a vinyl resin. The sheet 46 may carry an exposed coating 48- of heat-sealing 10 adhesive such as a coating of vinyl resin. Ad-

herent to the other side of the sheet 4l by an adhesive 49 is the layer 50 of metal foil. I'he adhesive 49 is preferably an insoluble adhesive.

When the composite flexible sheet material is composed as shown `in Fig. 7, the metal foil 50 is very eii'ectively protected from the contents of the tube, the exible composite sheet material being disposed so that the layer 48 of heat-sealing adhesive coating material is used as the inner surface of th'e tube. It will be noted that there are a plurality of layers of insoluble bonding material as well as a layer of waterproofed sheet cellulose material and a layer of fibrous material interposed between the interior of the tube and the metal foil. If desired, the sheet 45, if fibrous and absorbent. may be impregnated with an insoluble impregnating material.

In making the flexible composite sheet material, a variety of insoluble bonding agents may be used. For bonding the strain-resisting sheet to the metal foil, it is preferable to employ an adhesive resin such as DOlymerized vinyl acetate, vinyl acetate--vinvl chloride copolymer, sulfamideformaldehyde resin, or the like. Such adhesives are both waterand oil-insoluble. For certain purposes, an asphalt adhesive may be' used to bond the metal foil to the strain-resisting sheet material. Asphalt, while water-insoluble, has the disadvantage of being soluble in certain oils, however. For impregnating the strain-resisting sheetmaterial and causing it to adhere to other lamina, cellulosic lacquer, drying oils, synthetic resins and the like may be employed such as those above mentioned. Adhesives of the character aforesaid may likewise be used as the inner coating for the exible composite sheet material, since such adhesive materials provide a good normally non-sticky waterproofing coating and at the same time are thermoplastic so that opposed surfaces carrying the coating can be bonded together by heat-sealing.

It isv not essential that the inner or non-metallic surface of the flexible composite sheet material be coated throughout with a. heat-sealing type. of adhesive. In such case, the heat-sealing vtype of adhesive may be used only in the region erably, the metal foil is about-.00075 inch', or

somewhat greater, in thickness. The metal foil is preferably creped as set forth in my application, Ser. No. 464,034, but this is not essential to the practice of the present invention. The metal foil can advantageously be made of lead' which may, if desired, contain a very small amount of tin so as to improve its workability. When the flexible composite sheet material comprises strain-resisting sheet material and layers of impermeable cementitious bonding material, the contents of the tube are effectively prevented from contacting the lead, and by utilizing the special seam construction herein set forth, there is no danger of the contents of the tube contacting the lead foil in the region of the seam. However, other metal foils may be used such as tin, lead-tin,A alloys ranging from 1 to 99% of tin,

be fibrous in character, such as paper, e. g., im-

pregnated kraft paper, -fabric or the like, or it may be a continuous sheet such as sheet cellulose. A glassine paper, preferably laminated with waterproofing material between the lami nations, may also be employed. Such impervious glassine paper may be utilized to advantage in lieu of the layer of waterproofed sheet cellulose 46 referred to hereinabove in connection with Fig. 7.

The strain-resisting sheet of the character aforesaid is referred to broadly as non-metallic by way of contrast to the layer of metal foil that is adherent thereto. However, while this strainr'esisting sheet is referred to as non-metallic," this does not necessarily preclude the presence of an insoluble waterproofing material such as insoluble metal soaps or other salts or the presence of a filler or pigment material in the adhesive or in a coating for the strain-resisting sheet, which ller may be in the form of a metal oxide or the like.

While the flexible composite sheet material is shown in the drawings as of considerable thickness, the drawings have exaggerated the thickness of the flexible composite sheet material for purposes of clarity in the showing. As a matter of fact, the flexible composite sheet material can be made very thin and utilizing very little material. In such nexible composite sheet material, the metal foil is extremely thin and the amount of metal that is employed is only a minute fraction of metal required for making a tube having walls composed entirely of metal. Moreover, the present invention makes available inexpensive metal such as lead instead of a more lexpensive and rare metal such as tin. The flexible composite-sheet material is veryinexpenslve to produce and can readily beV formed into a tube in the practice of this invention.

While this invention has been described in connection with certain specific embodiments thereof, it is to be understood that this has been done for illustrative' purposes only.' and that the embodiments of this invention hereinabove described may be varied within' the scope of this invention as defined in the following claims:

I claim:

l. A tube of exible composite sheet material, said sheet material comprising a strain-resisting sheet of non-metallic sheet material the outer surface of which carries integral therewith a layer of metal foil, said tube being characterized by a longitudinally extending seam and by the fact that in the region of said seam longitudinally extending portions of the inner non-metal-l lic surface of said flexible composite sheet material are brought into juxtaposition and bonded face-to-face by an adhesive to provide a primary vseal which is the linitial juncture of said flexible composite sheet material that provides the inner surface of said tube, the layers of said primary seal being integrally arranged in the superposed order metal foil, non-metallic sheet, bonding aclhesive, non-metallic sheet, and metal foil, and by the further fact that one thickness of said composite sheet material is carried beyond said primary seal a substantial distance along the outer surface of said tube and is adherently bonded adjacent the end thereof `to said tube to provide side wall of said tube extending substantially completely thereabout so that the tube comprises 'a plurality of thicknesses of said composite sheet material substantially all around. said extension of said composite sheet material being adherently bonded to said tube as aforesaid by adhesive applied to the non-metallic surface thereof.

2. A tube of flexible composite sheet material. l

said ilexible composite sheet material comprising a strain-resisting sheet of non-metallic sheet material the outer surface of which carries integrally therewith a. layer of metal foil, said tube being characterized by a longitudinally extending seam and by the factn that in the region of said seam longitudinally extending portions of the inner non-metallic surface of said exible composite sheet material are brought into juxtaposition and are bonded face-to-face by an adhesive to provide a primary seal which is the initial juncture of said flexible composite sheet material that provides the inner surface of said tube, the layers of said primary seal being integrally arranged in the superposed order metal foil, nonmetallic sheet, bonding adhesive, non-metallic sheet, and metal foil, and by the further fact that one thickness of said composite sheet material is folded back on itself at said primary seal and is carried a substantial distance about the outside of said tube from said primary seal with said non-metallic surface of said flexible composite lsheet material outermost to provide an extension which is Wrapped at least once around said tube unti1 the end thereof overlies the non-metallic surface of said extension,` said end being turned under and adhesively bonded to an underlying portion of said extension so that non-metallic surface of said flexible composite sheet material adjacent the end of said extension is bonded face-to-face with non-metallic surface of said flexible composite sheet material also presented by said extension and with the layers of the composite material integrally arranged in the superposed order metal foil, nonmetallic sheet, bonding adhesive, non-metallic sheet and metal foil.

3. A tube`of flexible composite sheet material, said flexible composite sheet material comprising a strain-resisting sheet of non-metallic sheet material the outer surface of which carries integrally therewith a layer of metal foil, said tube being characterized by a longitudinally extending seam' and by the fact that in the region of said seam longitudinally extending portions of the inner non-metallic surface of said flexible composite sheet materialare brought into juXtawith the side carrying the metal foil outermost to provide an extension which extends substantially completely around the tube and which is adhesively bonded adjacent the end thereof to said tube.

4. A tube of flexiblecomposite sheet material said flexible composite sheet material comprising a fibrous strain-resisting sheet the outer surface of which carries integrally therewith a layer andas 13 of metal foil, said tube being characterized by the fact that said strain-resisting sheet comprises integrally bonded with the surface thereof that is opposite to the surface thereof carrying the metal foil an essentially non-porous cellulosic sheet material and said tube being further characterized by a longitudinally extending seam and by the fact that in the region of said seam longitudinally extending portions of the inner nonmetallic surface of said flexible composite sheet material are brought into juxtaposition with adhesive material therebetween and are bonded together face-to-face by said adhesive material thereby providing at said seam layers integrally arranged in the superposed order metal foil, non-metallic sheet, bonding adhesiva' nonmetallic sheet, and metal foil.

5. A method of making a tubeutilizing `flexible composite sheet material that comprises a strainresisting sheet o f non-metallic sheet material one surface of which carries integrally therewith a layer of metal foil, the opposite surface of said flexible composite sheet material being nonmetallic, said method comprising wrapping said flexible composite sheet material about a mandrel with the non-metallic surface thereof on the inside, bringing longitudinally extending portions of said non-metallic inner surface of -said flexible composite sheet material into juxtaposition in the region of initial juncture of said flexible composite shee't material and with heat sealing adhesive material between said juxtaposed portions, applying heat to seal together said juxtaposed portions ofnon-metallic surface of said flexible composite sheet material face-toface, carrying an extension consisting of one thickness of the ilexible composite sheet material beyond said region of initial juncture and wrapping same substantially completely about the previously formedtube with the folding back on itself of one thickness of said composite sheet material at said region of initial juncture, bringing the non-metallic surface of said extension adjacent the end of `said extension int'o juxtaposition with underlying peripheral surface of the tube with heat sealing adhesive between the last mentioned juxtaposed surfaces, and applying heat to seal together said last mentioned juxtaposed surfaces by means of said heat sealing adhesive therebetween.

6. A method of making a tube which comprises preparing flexible composite sheet material that comprises a fibrous strain-resisting sheet, a layer of metal foil integral with one side of said fibrous l sheet, and integral with the opposite side of saidv fibrous sheet an exposed coating of heat-sealing adhesive material, forming said flexible composite sheet material into a tube with said coating of heat-sealing adhesive on the interior, bringing longitudinally extending portions `oi' inner surface presenting said coating of said heat-sealing adhesive into'juxtaposition in the zone of initial juncture of said flexible composite sheet material, pressing `lsaid juxtaposed portions together arid applying heat thereto to bond together face-to-face said juxtaposed portions presenting said coating of heat-sealing adhesive material, carrying an extension consisting of one thickness of vsaid exible composite sheet material beyond said region of initial juncture and wrapping same substantially completely about the previously formed tube with folding back in itself of one thickness of said composite sheet material at said region of initial juncture, bringing surface of said extension presenting said coating of heatsealing adhesive that is adjacent the end of said extension into juxtaposition with underlying peripheral surface of said tube, and applying heat to seal `together said last mentioned juxtaposed surfaces by means of said coating of said heatsealing adhesive.

7. A method of making a tube utilizing flexible composite sheet material that comprises a strainresisting sheet of non-metallic sheet material p one surface of which carries integrally therewith a layer of metal foil, the opposite surface of said flexible composite lsheet material being nonmetallic, said method comprising forming said flexible composite sheet material into-a tube with said non-metallic surfacel innermost, bringing longitudinally extending portions of said nonmetallic surface of said flexible composite sheet material .into juxtaposition in the region of initial juncture of said flexible composite sheet material and with heat-sealing adhesive material between'said juxtaposed portions, applying heat to seal said juxtaposed portions face-to-face to provide a primary seal, wrapping an extension of the flexible composite sheet material about the previously formed tube with the non-metal` lic surface thereof outermost until the end of said extension overlies said exposed non-metallic surface of said flexible composite sheet material, turning under the end of said extension. and bonding the non-metallic surface of said turned-under end of said extension to underlying non-metallic surface of said extension of said flexible composite sheet material by a heat-sealing adhesive, heat being applied to effect said bond.

8. A method of making a tube utilizing flexible composite sheet material that comprises a strainresisting sheet of non-'metallic sheet material one surface of which carries integrally therewith a layer of metal foil, the opposite surface of 4said flexible composite sheet material being non-metallic, said method comprising forming said sheet material into a tube, bringing longitudinally extending portions of said non-metallic surface of said exible composite sheet material into juxtaposition with heat-sealing adhesive material therebetween, applying heat to bond together face-to-face said juxtaposed portions of said non-metallic surface of said flexible composite sheet material carrying an extension consisting of one thickness of said flexible composite sheet material beyond the region of initial juncture of said sheet material and wrapping same about the previously formed tube with folding back in itself of one thickness of said composite sheet material at said region of initial juncture, bringing the non-metallic surface of said extension adjacent the end of said extension into juxtaposition with underlying vsurface of said tube with heat-sealing adhesive between the last mentioned juxtaposed surfaces, and applying heat -to seal together said last mentioned juxtaposed surfaces by means of said heat-seal'- ing adhesive therebetween.

WALTER LANGER.

REFERENCIISy CITED The following references are of record in the ille ofv this patent:

UNITED STATES PATENTS 15 UNrrED STATES PATENTS Number Date Name Gearhart Nov. 18, 1919 Henderson Sept. 13, 1938 Sebattier Oct. 3, 1939 Ratay Oct. 17, 1939 Neumair Mar. 26, 1940 Berch ---1 May 13, 1941 Moore July 15, 1941 Hubner et; al. Aug. 19, 1941 Number Number 

